A new study from the Monell Center, published in the American Journal of Clinical Nutrition, shows how infants who have been introduced to starchy table foods, which often contain added salt, appear to have a greater preference for salty foods than infants who have not yet been introduced to these kinds of foods. The study reported infants eating starchy table foods consumed 55% more salt during a preference test than those who had not yet been exposed.

“More and more evidence is showing us that the first months of life constitute a sensitive period for shaping flavor preferences. In light of the health consequences of excess sodium intake, we asked if the effect of early experience extended to salt,” said lead author Leslie J. Stein, a physiological psychologist at Monell.

The study also noted that, upon reaching preschool age, the exposed infants were more likely to consume just plain salt, further weighing in on how the role of early dietary experience is shaping the salty taste preferences of infants and young children.

Senior author Gary Beauchamp, a behavioral biologist at Monell, said, “Because it’s been so hard to change adult intakes, we asked whether preferences might be influenced earlier in life through experience with salty food. If so, this may point to the development of public health initiatives that could help people reduce their salt intake.”

In the study, the salt preference of 61 infants was tested at two months of age and at six months of age. At each age, the infant was allowed to drink from three bottles for two minutes each. One bottle contained water, another contained a moderate concentration of salt (1%, about the saltiness of commercial chicken noodle soup) and the third bottle had a higher concentration of salt (2%, which tastes extremely salty to adults). Preference for salty taste was calculated at each age by comparing the amount the infant consumed of a given salt solution to the amount of water it consumed. Thus, if the infant drank more of the 1% salt solution than water, it was considered to have a preference for the 1%solution. Two-month-old infants were either indifferent to (1%) or rejected (2%) the salt solutions. At six months, salty taste preference of the same infants was related to previous exposure to starchy table food. The 26 infants already eating starchy foods preferred both salt solutions to water, while the 35 babies who had not yet been introduced to these foods remained indifferent to or continued to reject the salt solutions.

The researchers focused on starchy table foods because they include processed foods, which frequently are used as beginning foods and often contain added salt. Exposure to other types of table foods, such as fruit, was not associated with an increased preference for the taste of salt.

To explore whether the early effect extended into childhood, 26 of the children returned at preschool age. Mothers completed questionnaires about the children’s dietary behaviors, which revealed that the 12 children who were introduced to starchy table foods before six months of age were more likely to lick salt from foods and also were more likely to eat plain salt. These findings suggest that the early dietary exposure was related to an increased affinity for the taste of salt several years later.

“It’s important to note that our conclusions are limited by the correlational nature of the study,” said Stein. “Experimental studies are now needed to address the important question of how children and adults come to prefer high levels of salt in their food.”